A Miniature Circularly Polarized Microstrip Antenna Based on Radiation Cancellation

Abstract

In this paper, a miniature circularly polarized microstrip patch antenna has been designed for global positioning system (GPS) and beidou (BD) navigation applications. The proposed antenna consists of two stacked radiators fed by a Wilkinson power divider. By cancelling out the left-handed circular polarization (LHCP) fields in the backward direction and superposing right-handed circular polarization (RHCP) fields in the broadside direction, which are radiated by two radiators, the proposed antenna radiates a RHCP wave with a front-to-back ratio of 14 dB in the L1 GPS and B1 BD bands. With the radiation cancellation, the proposed GPS antenna has a compact size of 50mm×50mm×12mm. Good agreement between the measurement and the simulation are observed to demonstrate good radiation performance and miniature size of the proposed antenna.